Is bad sweats, cold chills jaw pain any sign of withdrawl from my methadone?

my husband been on methadone for 6 mos now and lately he has had really bad sweats and cold chills and jaw pain and his bones hurt he takes 20mg at 5am and by 7pm he feels all these signs so he takes 20mg more and starts to feel a little better not 100% though. what can be causing these feelings? thank you